While, as will be better understood from the following discussion, the present invention was developed for use on board aircraft to assist the pilot in achieving a desired objective, and is described in such an environment, it is to be understood that the invention is also useful in other environments, particularly vehicular environments to provide a similar result. Also, as will be better understood from the following discussion, as used herein, the term "desired objective" covers a multitude of objectives, including both the avoidance of potentially hazardous incidents (e.g., an aircraft not stopping or not taking off before reaching the end of a runway) and the achievement of desirable results (such as an aircraft's speed dropping to a desired value when a particular exit ramp is reached after a landing).
Modern commercial aircraft include a wide variety of warning and caution signals designed to assist a pilot in accomplishing a safe flight from takeoff to landing. The warning and caution signals are designed to advise the pilot of the occurrence of a condition that could prevent the achieving of a safe flight. While it is difficult to establish an exact definition of the difference between warning and caution signals, the most common definition appears to be that a warning signal signifies a condition to which a relatively immediate response must be made, and a caution signal is one to which a response may be safely delayed for some time period. In either case, warning and caution signals advise the pilot that a particular condition has occurred that may have an effect on the accomplishment of a safe flight between takeoff and landing. However, the pilot is not advised as to how soon he must take action in order to prevent the condition from frustrating his ability to achieve a safe flight. In many instances, such information is desirable. That is, in many situations, an indication of the time in which action must be taken to avoid the occurrence of an event that will prevent the accomplishment of the pilot's main objective would be valuable. An example of a situation in which such an indication would be helpful is that of an overshot touchdown on a slippery runway. Whether to try to stop the aircraft or to "go around" is now merely a matter of pilot judgement. In many instances, the proper decision is difficult to make. A clear indication of whether or not there is adequate time to make a stop under existing conditions would aid the pilot in such a situation to make the correct decision. Another situation currently requiring pilot judgment is the rejected "take-off" situation. This situation is particularly difficult to judge if it is precipitated by trouble other than engine failure. Current procedure uses indicated airspeed as a go/stop criterion in rejected take-off situations. This criterion is adequate if engine failure is the cause of the refused take-off situation, but inadequate if the refused take-off situation is caused by other factors. An indication to the pilot of whether or not a safe take-off and/or a safe stop can be achieved under a wide variety of existing conditions would greatly enhance the pilot's ability to make the correct decision. A further situation is one wherein the aircraft is sinking on approach and a determination must be made to either attempt to land or "go-around" and make another landing approach. An indication to the pilot of whether or not a safe landing and/or a safe go-around can be achieved under existing conditions would also greatly enhance the pilot's ability to make the correct decision.
In summary, a method of and an apparatus for providing a pilot with interactive information adapted to assist him in making the proper decision under many situations by providing him with an indication of the time in which action must be taken in order to accomplish a desired objective is desirable. Such a method and apparatus that can be alternatively used to automatically control certain aspects of an aircraft to achieve the desired objective is also desirable. For purposes of description, the interval of time in which action must be taken to achieve a desired objective is herein denoted the chronodrasic interval. The word chronodrasic is derived from Greek and means literally time for action (chronos-time, drasis-action).
It is an object of this invention to provide a method of and an apparatus for continuously determining chronodrasic intervals.
It is another object of this invention to provide a method of and an apparatus for continuously determining the chronodrasic interval related to the achievement of a desired objective.
It is a still further object of this invention to provide a method of and an apparatus for continuously determining the chronodrasic interval related to a particular situation and provide interactive information suitable for apprising a human operator of the need to take action and the effectiveness of the action taken.
It is a still further object of this invention to provide an apparatus for continuously determining chronodrasic intervals related to a particular situation(s) and provide control signals suitable for controlling a display that provides interactive information suitable for apprising a human operator of the need to take action and the effectiveness of the action taken or suitable for use by automatic control systems adapted to take similar action automatically.